Understanding function objects

Function objects, also known as functors, are used for generating, testing, and operating on data. If you declare an object as a functor, you can use that object as one would use a function call. Oftentimes, the algorithms in the STL need a parameter to perform their designated tasks. Functors tend to be a useful way to assist in performing those tasks. In this section, we will learn about the following:

• Functors
• Internal and external iterators
• Generators
• Implicit iterators

Functors

A functor is a functional programming paradigm in which a transformation is performed on a structure while the structure is preserved.

In our example, we take an integer slice, intSlice, and lift the slice into...